PROJECT ABSTRACT In the research proposed here, we will evaluate the strategies nursing homes (NHs) use to prevent adverse safety events affecting residents with obesity and develop an evidence-based toolkit to help NHs adapt to the increasing care challenges for residents with obesity. Thirty percent of the 1.4 million NH residents in the U.S. are obese, and every day, resident obesity makes it more difficult to provide safe, high-quality nursing and custodial care in the more than 15,000 NHs in the U.S. Obese residents require much more nursing and custodial assistance with daily activities such as mobility, toileting, and skin assessments. NH residents with obesity are at high risk for adverse safety events such as preventable pressure ulcers, infections, falls, and hospital readmissions. To cope with these challenges, NHs may adapt to the needs of obese residents and prevent adverse safety events through organizational adaptation strategies that utilize some combination of more staff members, more staff time, more equipment, specialized nursing units, or even avoiding admission of obese individuals. It is not known which adaptation strategies predominate across NHs, which adaptation strategies are associated with improved health and safety, or which adaptation strategies are associated with increased adverse safety events. Due to these safety concerns and the lack of evidence-based adaptation strategy recommendations, there is a critical need to perform a large-scale evaluation of the adaptation strategies NHs use to maintain the health and safety of obese residents and associate these methods with other key facility characteristics and individual outcomes. We propose the following aims to improve safety for residents with obesity in NHs. In Aim 1, we will prioritize and determine the prevalence of the safety concerns and available adaptations for residents with obesity through structured research observations of care delivery, semi-structured interviews of stakeholders, and a large national survey of NHs. In Aim 2, we will examine the relationship between different types of adaptation strategies and a resident adverse safety events composite outcome, including pressure ulcers, wound infections, urinary tract infections, falls, and hospital readmissions, using national NH assessment data. In Aim 3, we will develop and validate a toolkit for decision makers and caretakers to facilitate implementation of the most effective adaptation strategies in NHs. This work will provide qualitative and quantitative evidence-based research and develop evidence-based tools to help implement improved safety and care of hundreds of thousands of vulnerable NH residents with obesity.